Add support for STM8

[brainstorm]

Hello @wargio,

I'll test my luck and your patience as I did with #178, thanks so much again for that one, btw 🙏🏻 ... would it be possible to have STM8 support for my other hobby project in https://github.com/brainstorm/threadmill-re?

Cheers!

[wargio]

Unfortunately not in the short future, but feel free to try to add this by following the documentation here: https://github.com/wargio/r2dec-js/blob/master/DEVELOPERS.md

[wargio]

Is there an ISA manual for this?

https://www.digikey.hk/htmldatasheets/production/1990666/0/0/1/stm8-cpu-programming-manual.html